Reverse DNS query - PTR records ..

My linux box has two interfaces eth0 and eth1 configured with 10.232.19.100 and 192.168.1.1 respectively .

But as soon as the box is restarted , the box send reverse dns query (PTR ) to nameserver defined in /etc/resolv.conf file .
1. why this reverse dns query is sent out ? Can i assign any name to these interfaces so that it wont query a PTR records .

i defined entries in /etc/hosts file for eth0 and eth1 , and defined /etc/host.conf . But still it sends out reverse dns query .

2 . Why it is not picking entries from /etc/hosts file .
3 . There is a reverse dns query for 192.168.1.0 also . WHy it is so ?

but if i add
nameserver 127.0.0.1 then everything seems to work fine .How this is possible since no dns server running on my linux box . But if i make changes in /etc/hosts file , it takes reboot to take effect .

You have a network defined as 192.168.1.0 by the nature of having a nic with the ip address of 192.168.1.1 - why would you NOT expect the server to try and contact the nameserver listed as responsible for the 192.168.1.0 network to check that there is a ptr record for 192.168.1.1?